Impact of Maternal HIV Seroconversion during Pregnancy on Early Mother to Child Transmission of HIV (MTCT) Measured at 4-8 Weeks Postpartum in South Africa 2011-2012: A National Population-Based Evaluation

Abstract

BackgroundMother-to-child transmission of HIV (MTCT) depends on the timing of HIV infection. We estimated HIV-seroconversion during pregnancy (HSP) after having a HIV-negative result antenatally, and its contribution to early MTCT in South Africa (SA).Methods and FindingsBetween August 2011 and March 2012, we recruited a nationally representative sample of mother-infant pairs with infants aged 4-to-8 weeks from 578 health facilities. Data collection included mother interviews, child health-card reviews, and infant dried-blood-spots sample (iDBS). iDBS were tested for HIV antibodies and HIV-deoxyribonucleic-acid (HIV-DNA). HSP was defined as maternal self-report of an HIV-negative test during this pregnancy, no documented use of antiretroviral drugs and a matched HIV sero-positive iDBS. We used 20 imputations from a uniform distribution for time from reported antenatal HIV-negative result to delivery to estimate time of HSP. Early MTCT was defined based on detection of HIV-DNA in iDBS. Estimates were adjusted for clustering, nonresponse, and weighted by SA’s 2011 live-births.ResultsOf 9802 mother-infant pairs, 2738 iDBS were HIV sero-positive, including 212 HSP, resulting in a nationally weighted estimate of 3.3% HSP (95% Confidence Interval: 2.8%-3.8%). Median time of HIV-seroconversion was 32.8weeks gestation;28.3% (19.7%- 36.9%) estimated to be >36 weeks. Early MTCT was 10.7% for HSP (6.2%-16.8%) vs. 2.2% (1.7%-2.8%) for mothers with known HIV-positive status. Although they represent 2.2% of all mothers and 6.7% of HIV-infected mothers, HSP accounted for 26% of early MTCT. Multivariable analysis indicated the highest risk for HSP was among women who knew the baby’s father was HIV-infected (adjusted-hazard ratio (aHR) 4.71; 1.49-14.99), or who had been screened for tuberculosis (aHR 1.82; 1.43-2.32).ConclusionsHSP risk is high and contributes significantly to early MTCT. Identification of HSP by repeat-testing at 32 weeks gestation, during labor, 6 weeks postpartum, in tuberculosis-exposed women, and in discordant couples might reduce MTCT.

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“I Did Not Want to Give Birth to a Child Who has HIV”: Experiences Using PrEP During Pregnancy Among HIV-Uninfected Kenyan Women in HIV-Serodiscordant Couples

“…Pregnant women who become acutely infected with HIV are estimated to account for 26% of all mother-to-child HIV transmissions (MTCT) in high HIV prevalence settings 4,5 . Pre-exposure prophylaxis (PrEP) decreases HIV incidence in adherent women 6–10 .…”

Delivering preexposure prophylaxis to pregnant and breastfeeding women in Sub-Saharan Africa

“…HIV acquisition during pregnancy and postpartum periods remains high despite increased access to and initiation of antiretroviral therapy (ART) in sub-Saharan Africa [1–5]. There are biological and behavioural factors that drive high HIV incidence during pregnancy and breastfeeding periods such as hormonal changes that alter genital mucosal surfaces, and frequent condomless sex with HIV-infected partners or partners of unknown serostatus [3, 6–9].…”